Put it this way, I usually go over the France/Belgium border at about 100mph... there's just a sign saying "Welcome to France" on the side of the motorway. Very underwhelming.

Bah...if it would read "Welcome to France, the land of the Eiffel tower, champagne, wine, brie, baguettes, lavender and tollways. Enjoy your stay in our beautiful country! " it would, apart from being a HUGE sign, be very difficult to read at the speed you're passing it!

BTW, a small but maybe useful fact : the french police's radar's are triggered from 150 km/h and up.